Secure point of sale terminal

ABSTRACT

A data entry device including a housing formed of at least two portions, data entry circuitry located within the housing, at least one case-open switch assembly operative to sense when the housing is opened and tamper indication circuitry operative to receive an input from the at least one case-open switch assembly and to provide an output indication of possible tampering with the data entry circuitry located within the housing, the at least one case-open switch assembly including an arrangement of electrical contacts including at least first, second and third contacts and a displaceable conductive element, the tamper indication circuitry and the third contact together being operative such that when the third contact is short circuited to at least one of the first contact, the second contact and another contact, an output indication of possible tampering is provided.

REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/082,704, filed Nov. 18, 2013, titled SECURE POINT OF SALE TERMINAL,which is a continuation of U.S. patent application Ser. No. 12/666,054,filed Aug. 1, 2011, titled SECURE POINT OF SALE TERMINAL, now U.S. Pat.No. 8,595,514, which is a U.S. National Phase application of PCTApplication No. PCT/IL2009/000724, filed Jul. 23, 2009, titled SECUREPOINT OF SALE TERMINAL, which is continuation-in-part of U.S. patentapplication Ser. No. 12/355,857, filed Jan. 19, 2009, titled SECUREDKEYPAD DEVICES, which claims priority of U.S. Provisional PatentApplication Ser. No. 61/011,993, filed Jan. 22, 2008, titled SECUREDKEYPAD DEVICES, the disclosures of which are incorporated by reference.

Reference is made to the following patent and patent applications, ownedby assignee, the disclosures of which are hereby incorporated byreference, which are believed to relate to subject matter similar to thesubject matter of the present application:

U.S. Pat. No. 6,853,093 and U.S. Published Patent Application Nos.2008/0135617 and 2007/0152042.

FIELD OF THE INVENTION

The present invention relates generally to secure keypad devices andmore particularly to data entry devices having anti-tamperfunctionality.

BACKGROUND OF THE INVENTION

The following U.S. patent Publications are believed to represent thecurrent state of the art and are hereby incorporated by reference:

-   U.S. Published Patent Application No. 2008/0278353;-   U.S. Pat. Nos. 7,270,275; 6,646,565; 6,917,299 and 4,486,637;-   European Patent Nos.: 1421549 and 1676182; and-   Great Britain Patent Application No. GB8608277.

SUMMARY OF THE INVENTION

The present invention seeks to provide improved secure keypad devices.

There is thus provided in accordance with a preferred embodiment of thepresent invention a data entry device including a housing formed of atleast two portions, data entry circuitry located within the housing, atleast one case-open switch assembly operative to sense when the housingis opened and tamper indication circuitry operative to receive an inputfrom the at least one case-open switch assembly and to provide an outputindication of possible tampering with the data entry circuitry locatedwithin the housing, the at least one case-open switch assembly includingan arrangement of electrical contacts including at least first, secondand third contacts and a displaceable conductive element, which definesa short circuit between the first and second contacts only when thehousing is closed, the third contact being arranged between the firstand second contacts and the displaceable conductive element so as tonormally not be short circuited to the first and second contacts whenthe housing is closed, the tamper indication circuitry and the thirdcontact together being operative such that when the third contact isshort circuited to at least one of the first contact, the second contactand another contact, an output indication of possible tampering isprovided.

In accordance with a preferred embodiment of the present invention, atleast one of the first contact, the second contact and another contactis connected to the tamper indication circuitry. Preferably, the first,second and third contacts are concentric. Additionally or alternatively,at least two of the first, second and third contacts are concentricrings.

In accordance with a preferred embodiment of the present invention, thehousing includes a top housing portion including key apertures, aplurality of data entry keys are mounted in the housing to have dataentry key depression travel paths in the housing, the plurality of dataentry keys being associated with a substrate, which is disposed belowthe top housing portion and anti-tampering electrical conductors arearranged between the top housing portion and the substrate thereby toprevent unauthorized access to the substrate.

Preferably, the substrate is a flexible substrate. Additionally oralternatively, the anti-tampering electrical conductors are disposedperipherally of the substrate.

In accordance with a preferred embodiment of the present invention, thedata entry device also includes a plurality of key switch contactsmounted on the substrate and arranged to be displaced into or out ofelectrical contact with a corresponding plurality of electrical switchesby depression of corresponding ones of the plurality of data entry keysto at least a predetermined extent along corresponding ones of the dataentry key depression travel paths.

In accordance with a preferred embodiment of the present invention, thedata entry device also includes a plurality of key switch contactsmounted on the plurality of data entry keys and arranged to be displacedinto or out of electrical contact with a corresponding plurality ofelectrical switches by depression of corresponding ones of the pluralityof data entry keys to at least a predetermined extent alongcorresponding ones of the data entry key depression travel paths.

Preferably, the plurality of data entry keys are integrally formed withthe substrate.

In accordance with a preferred embodiment of the present invention, theanti-tampering electrical conductors are electrically connected toanti-tampering detection circuitry. Additionally or alternatively, theanti-tampering electrical conductors are disposed above and below thesubstrate. Additionally, the anti-tampering electrical conductors abovethe substrate and the anti-tampering electrical conductors below thesubstrate are electrically connected to anti-tampering detectioncircuitry. Additionally or alternatively, the anti-tampering electricalconductors above the substrate are electrically connected to theanti-tampering electrical conductors below the substrate.

In accordance with a preferred embodiment of the present invention, thehousing includes a plurality of data entry keys, the data entry keyshaving data entry key depression travel paths in the housing, aplurality of key switch contacts are mounted on a flexible substrateseparate from the plurality of data entry keys and arranged to bedisplaced into or out of electrical contact with a correspondingplurality of electrical switches by depression of corresponding ones ofthe plurality of data entry keys to at least a predetermined extentalong corresponding ones of the data entry key depression travel pathsand anti-tampering electrical conductors are arranged with respect tothe plurality of key switch contacts thereby to prevent unauthorizedelectrical contact therewith.

Preferably, the anti-tampering electrical conductors are disposed aboveand below the flexible substrate. Additionally, the anti-tamperingelectrical conductors above the flexible substrate and theanti-tampering electrical conductors below the flexible substrate areelectrically connected to anti-tampering detection circuitry.Alternatively or additionally, the anti-tampering electrical conductorsabove the flexible substrate are electrically connected to theanti-tampering electrical conductors below the flexible substrate.

In accordance with a preferred embodiment of the present invention, theplurality of data entry keys are integrally formed with the housing.

There is thus provided in accordance with a preferred embodiment of thepresent invention a data entry device including a housing including atop housing portion including key apertures, a plurality of data entrykeys mounted in the housing to have data entry key depression travelpaths in the housing, the plurality of data entry keys being associatedwith a substrate, which is disposed below the top housing portion; andanti-tampering electrical conductors arranged between the top housingportion and the substrate thereby to prevent unauthorized access to thesubstrate.

Preferably, the substrate is a flexible substrate. In accordance with apreferred embodiment of the present invention the anti-tamperingelectrical conductors are disposed peripherally of the substrate.

In accordance with a preferred embodiment of the present invention thedata entry device also includes a plurality of key switch contactsmounted on the substrate and arranged to be displaced into or out ofelectrical contact with a corresponding plurality of electrical switchesby depression of corresponding ones of the plurality of data entry keysto at least a predetermined extent along corresponding ones of the dataentry key depression travel paths. Alternatively, the data entry deviceincludes a plurality of key switch contacts mounted on the data entrykeys and arranged to be displaced into or out of electrical contact witha corresponding plurality of electrical switches by depression ofcorresponding ones of the plurality of data entry keys to at least apredetermined extent along corresponding ones of the data entry keydepression travel paths.

Preferably, the plurality of data entry keys are integrally formed withthe substrate. In accordance with a preferred embodiment of the presentinvention the anti-tampering electrical conductors are electricallyconnected to anti-tampering detection circuitry.

Preferably, the anti-tampering electrical conductors are disposed aboveand below the substrate. Additionally, the anti-tampering electricalconductors above the substrate and the anti-tampering electricalconductors below the substrate are electrically connected toanti-tampering detection circuitry. Additionally or alternatively, theanti-tampering electrical conductors above the substrate areelectrically connected to the anti-tampering electrical conductors belowthe substrate.

There is also provided in accordance with another preferred embodimentof the present invention a data entry device including a housingelement, including a plurality of data entry keys disposed therein, thedata entry keys having data entry key depression travel paths in thehousing element, a plurality of key switch contacts mounted on aflexible substrate separate from the plurality of data entry keys andarranged to be displaced into or out of electrical contact with acorresponding plurality of electrical switches by depression ofcorresponding ones of the plurality of data entry keys to at least apredetermined extent along corresponding ones of the data entry keydepression travel paths and anti-tampering electrical conductorsarranged with respect to the plurality of key switch contacts thereby toprevent unauthorized electrical contact therewith.

Preferably, the anti-tampering electrical conductors are disposed aboveand below the flexible substrate. Additionally, the anti-tamperingelectrical conductors above the flexible substrate and theanti-tampering electrical conductors below the flexible substrate areelectrically connected to anti-tampering detection circuitry.Alternatively or additionally, the anti-tampering electrical conductorsabove the substrate are electrically connected to the anti-tamperingelectrical conductors below the substrate.

In accordance with a preferred embodiment of the present invention theplurality of data entry keys are integrally formed with the housingelement.

There is further provided in accordance with yet another preferredembodiment of the present invention data entry device including ahousing element, including a plurality of data entry keys disposedtherein, a plurality of housing-open indicating switch contacts andanti-tampering electrical conductors disposed effectively surroundingthe plurality of housing-open indicating switch contacts thereby toprevent unauthorized electrical contact therewith.

In accordance with a preferred embodiment of the present invention theanti-tampering electrical conductors are electrically connected toanti-tampering detection circuitry.

Preferably, the plurality of data entry keys are integrally formed withthe housing element.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are simplified exploded view illustrations, taken inrespective opposite directions, of a secure keypad device constructedand operative in accordance with a preferred embodiment of the presentinvention;

FIG. 1C is a simplified pictorial and sectional illustration of theassembled secure keypad device of FIGS. 1A and 113;

FIGS. 2A and 2B are simplified exploded view illustrations, taken inrespective opposite directions, of a secure keypad device constructedand operative in accordance with another preferred embodiment of thepresent invention;

FIG. 2C is a simplified pictorial and sectional illustration of theassembled secure keypad device of FIGS. 2A and 2B;

FIG. 3 is a simplified illustration of electrical connections betweenantis tampering elements in the embodiments of FIGS. 1A-2C;

FIGS. 4A and 4B are simplified exploded view illustrations, taken inrespective opposite directions, of a secure keypad device constructedand operative in accordance with a further preferred embodiment of thepresent invention;

FIG. 4C is a simplified illustration the secure keypad device of FIGS.4A and 4B at various levels of disassembly;

FIG. 5 is a simplified illustration of electrical connections betweenanti-tampering elements in the embodiments of FIGS. 4A-4C;

FIGS. 6A and 6B are simplified exploded view illustrations, taken inrespective opposite directions, of a secure keypad device constructedand operative in accordance with yet a further preferred embodiment ofthe present invention;

FIG. 7 is a simplified illustration of electrical connections betweenanti-tampering elements in the embodiments of FIGS. 6A and 6B;

FIG. 8 is a simplified exploded view illustration of a secure keypaddevice constructed and operative in accordance with a still furtherpreferred embodiment of the present invention;

FIGS. 9A and 9B are simplified sectional illustrations of part of thedevice of FIG. 8, taken along lines IX-IX in FIG. 8, in respective keynon-depressed and key depressed operative orientations;

FIG. 10 is a simplified exploded view illustration of a secure keypaddevice constructed and operative in accordance with a yet furtherpreferred embodiment of the present invention;

FIGS. 11A & 11B are simplified sectional illustrations of part of thedevice of FIG. 10, taken along lines XI-XI in FIG. 10, in respective keynon-depressed and key depressed operative orientations;

FIGS. 12A and 12B are simplified exploded view illustrations, taken inrespective opposite directions, of a secure keypad device constructedand operative in accordance with still another preferred embodiment ofthe present invention;

FIG. 13A is a simplified partially sectional, partially schematicillustration of a first embodiment of a case open switch in a closedoperative orientation;

FIG. 13B is a simplified sectional illustration of the first embodimentof a case open switch of FIG. 13A in an open operative orientation; and

FIG. 14A is a simplified partially sectional, partially schematicillustration of a second embodiment of a case open switch in a closedoperative orientation; and

FIG. 14B is a simplified sectional illustration of the second embodimentof a case open switch of FIG. 14A in an open operative orientation.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Reference is now made to FIGS. 1A, 1B and 1C, which illustrate a securekeypad device constructed and operative in accordance with a preferredembodiment of the present invention.

As seen in FIGS. 1A, 1B and 1C, there is provided a secure keypad device100 including a housing element 102 which, together with a back panel(not shown), defines a keypad device housing. Housing element 102includes, on a top surface 104 thereof; a display aperture 106, throughwhich a display (not shown) may be viewed, and an array 108 of keyapertures 110.

A key mat 112, preferably formed of a resilient plastic or rubber,defines a plurality of depressible keys 114, preferably integrallyformed with mat 112, which partially extend through key apertures 110. Aflexible resilient protective partial enclosure 116, which includes ananti-tampering grid 118, formed of a multiplicity of interconnectedanti-tampering electrical conductors, on a top surface 120 thereof andon side surfaces 122 thereof, is provided. A flexible cable 124 iscoupled to grid 118.

Disposed within protective partial enclosure 116, underlying top surface120, is a key contact pad 130. Key contact pad 130 is preferably aresilient, generally planar, pad formed of flexible and resilientplastic or rubber, having an array 132 of raised resilient conductivedomes 134, such as those commercially available from Snaptron, Inc. ofWindsor, Colo., USA.

Disposed in predetermined spaced relationship with key contact pad 130is an electrical circuit board 140, which functions, inter alia, as akey contact board, defining a plurality of pairs of adjacent electricalcontact pads 142, each pair underlying a corresponding dome 134,preferably made of carbon, metal or combination of carbon/metal. Thearrangement of key contact pad 130 and of electrical circuit board 140is such that depression of a key 114 by the finger of a user causes dome134 to establish electrical contact with and between a correspondingpair of electrical contact pads 142 lying thereunder and in registrationtherewith. When key 114 is not depressed, no electrical contact existsbetween dome 134 and a pair of corresponding electrical contact pads 142or between the adjacent pads of the pair.

Electrical circuit board 140 preferably includes an anti-tampering grid144 formed of a multiplicity of interconnected anti-tampering electricalconductors. An electrical connector 146 is arranged for matingconnection with flexible cable 124. The anti-tampering grids 118 and 144are coupled to anti-tampering detection circuitry 148.

In accordance with a preferred embodiment of the present invention,case-open switches, which sense physical tampering and opening of thehousing, are provided, preferably within partial enclosure 116. In theillustrated embodiment, the case-open switches are each embodied in araised resilient dome 150, preferably formed of a conductor, mounted onkey contact pad 130. The domes may be discrete units or arrays, such asthose commercially available from Snaptron, Inc. of Windsor, Colo., USA.Domes 150 preferably extend outwardly from the surface of key contactpad 130 to a greater extent than do domes 134.

Disposed on electrical circuit board 140 underlying each of domes 150are a corresponding number of arrays 152, each preferably comprising aplurality of mutually concentric conductive pads, such as rings, eacharray underlying a corresponding dome 150. The arrangement of keycontact pad 130 and of electrical circuit board 140 is preferably suchthat as long as the housing is closed, domes 150 each are in electricalcontact with some but not all of the plurality of mutually concentricconductive rings in each of arrays 152 underlying domes 150 and inregistration therewith.

In accordance with a first embodiment of the invention, indicated inFIG. 1A as Option A, each array 152 comprises an outer ring 153, anintermediate ring 154 and an inner ring 155. In this embodiment, as longas the housing is closed and not tampered with, the dome 150 is inelectrical contact with outer ring 153 and inner ring 155 but not withintermediate ring 154. Dome 150 is normally in electrical contact withouter ring 153. Preferably, dome 150 is soldered to outer ring 153. Iftampering is attempted, electrical contact is made between intermediatering 154 and at least one of dome 150, outer ring 153 and inner ring155.

In accordance with a second embodiment of the invention, indicated inFIG. 1A as Option B, each array 152 comprises an outermost ring 156, asecond to outermost ring 157, an outer intermediate ring 158, an innerintermediate ring 159 and an inner ring 160, in this embodiment, as longas the housing is closed and not tampered with, the dome 150 is inelectrical contact with outer intermediate ring 158 and inner ring 160but not with any of outermost ring 156, second to outermost ring 157 andinner intermediate ring 159. Dome 150 is normally in electrical contactwith outer intermediate ring 158. Preferably, dome 150 is soldered toouter intermediate ring 158. If tampering is attempted, electricalcontact is made between at least one of outermost ring 156, second tooutermost ring 157 and inner intermediate ring 159 and at least one ofdome 150, outer intermediate ring 158 and inner ring 160.

Reference is now made additionally to FIGS. 13A and 13B and to FIGS. 14Aand 1413, which are simplified partially sectional and partiallyschematic illustrations of respective first and second embodiments ofthe case open switch in respective closed and open operativeorientations, coupled to case tamper detection circuitry.

As seen in FIGS. 13A and 13B, electrical contact between each dome 150and corresponding ring 155 is ensured by the provision of a pin 161,preferably integrally formed on housing element 102. When the housing isclosed, pins 161 urge corresponding protrusions 162 in key mat 112towards partial enclosure 116 and urge partial enclosure 116 and thuscorresponding domes 150 towards ring 155 of array 152. In an alternativeembodiment, where partial enclosure 116 is not provided, when thehousing is closed, pins 161 urge corresponding protrusions 162 in keymat 112 and thus corresponding domes 150 towards arrays 152.

As seen in FIG. 13A, outer ring 153 is grounded, intermediate ring 154is coupled to a voltage VDD via a resistor R1 and inner ring 155 iscoupled to a voltage VDD via a resistor R2. A voltage V2 may be measuredto indicate whether the housing is open or closed, i.e. whether or notdome 150 is simultaneously in contact with both inner ring 155 and outerring 153.

When this simultaneous contact exists, V2 is zero; otherwise V2 equalsVDD. An attempt to tamper with the switch by short circuiting inner ring155 and outer ring 153 will also short circuit intermediate ring 154 andmay be detected by measuring a voltage V1. During normal operation,where no tampering is detected, V1 is equal to VDD. An attempt to tamperwith the case open switch causes voltage V1 to be zero.

As seen in FIGS. 14A and 1413, electrical contact between each dome 150and corresponding ring 160 is ensured by the provision of pin 161,preferably integrally formed on housing element 102. When the housing isclosed, pins 161 urge corresponding protrusions 162 in key mat 112towards partial enclosure 116 and urge partial enclosure 116 and thuscorresponding domes 150 into electrical contact with rings 160. In analternative embodiment, where partial enclosure 116 is not provided,when the housing is closed, pins 161 urge corresponding protrusions 162in key mat 112 and thus corresponding domes 150 towards rings 160.

When attempted tampering occurs and the housing is opened, no electricalcontact exists between domes 150 and corresponding rings 155 (FIG. 13B)or 160 (FIG. 14B) and a suitable alarm and/or disablement occurs.

As seen in FIG. 14A, inner ring 160 is coupled to a voltage VCC via aresistor R2, inner intermediate ring 159 is coupled to voltage VCC viaresistor R1, and outer intermediate ring 158 is grounded. Outermost ring156 is grounded and second to outermost ring 157 is coupled to voltageVCC via resistor R1.

A voltage at tamper detection input points TD2 may be measured toindicate whether the hosing is open or closed, i.e. whether or not dome150 is simultaneously in contact with both inner ring 160 and outerintermediate ring 158. When this simultaneous contact exists, voltagemeasured at TD2 is zero; otherwise voltage measured at TD2 equals VCC.Thus, an attempt to remove of adequate pressure from the dome 150 andopen the housing triggers a tamper response.

An attempt to tamper with the switch, for example by applying pressureto the snap dome, such as by drilling a hole in the dome or by injectionof conductive glue, results in short circuiting inner ring 160 and outerintermediate ring 158 and inner intermediate ring 159 and may bedetected by measuring a voltage at nTD3. During normal operation, whereno tampering is detected, voltage measured at nTD3 is equal to VCC. Anattempt to tamper with the case open switch causes voltage measured atnTD3 to be zero.

It is appreciated that the rings of array 152, both in Option A andOption B and corresponding FIGS. 13A & 13B and FIGS. 14A & 14B, can beof any suitable shape, such as circular or elliptical shape and arepreferably concentric.

Disposed below electrical circuit board 140, there is provided aperipheral protective grid element 163 which includes an anti-tamperinggrid 164, preferably coupled to a flexible cable 165, which is in turnconnected to a connector 166 on electrical circuit board 140. Peripheralprotective grid element 163 preferably is located interiorly of the sidesurfaces 122 of enclosure 116. Fixedly attached to peripheral protectivegrid element 163 and preferably disposed therebelow is a bottomprotective grid element 168 which includes an anti-tampering grid 170,which is coupled via contacts 172 and via a connector 174 which extendsthrough an aperture 176 formed in peripheral grid element 163 intoelectrical contact with contacts 178 on electrical circuit board 140.The anti-tampering grids 164 and 170 are coupled to anti tamperingdetection circuitry 148.

Reference is now made to FIGS. 2A, 2B and 2C, which illustrate a securekeypad device constructed and operative in accordance with anotherpreferred embodiment of the present invention.

As seen in FIGS. 2A-2C, there is provided a secure keypad device 200including a housing element 202 which, together with a back panel (notshown), defines a keypad device housing. Housing element 202 includes,on a top surface 204 thereof, a display aperture 206, through which adisplay (not shown) may be viewed, and an array 208 of key apertures210.

A key mat 212, preferably formed of a resilient plastic or rubber,defines a plurality of depressible keys 214, preferably integrallyformed with mat 212, which partially extend through key apertures 210. Aflexible resilient protective partial enclosure 216, which includes ananti-tampering grid 218, formed of a multiplicity of interconnectedanti-tampering electrical conductors, on a top surface 220 thereof andon side surfaces 222 thereof, is provided. A flexible cable 224 iscoupled to grid 218.

Disposed within protective partial enclosure 216, underlying top surface220, is a key contact pad 230. Key contact pad 230 is preferably aresilient, generally planar, pad formed of flexible and resilientplastic or rubber, having an array 232 of raised resilient domes 234having conductors 236 formed on corresponding bottom facing surfaces 238thereof.

Disposed in predetermined spaced relationship with key contact pad 230is a electrical circuit board 240, which functions, inter alia, as a keycontact hoard, defining a plurality of pairs of adjacent electricalcontact pads 242, each pair underlying a corresponding conductor 236.The arrangement of key contact pad 230 and of electrical circuit board240 is such that depression of a key 214 by the finger of a user causesconductor 236 to establish electrical contact with and between acorresponding pair of electrical contact pads 242 lying thereunder andin registration therewith. When key 214 is not depressed, no electricalcontact exists between conductor 236 and a pair of correspondingelectrical contact pads 242 or between the adjacent pads of the pair.

Electrical circuit board 240 preferably includes an anti-tampering grid244 formed of a multiplicity of interconnected anti-tampering electricalconductors. An electrical connector 246 is arranged for matingconnection with flexible cable 224. The anti-tampering grids 218 and 214are coupled to anti-tampering, detection circuitry 248.

In accordance with a preferred embodiment of the present invention,case-open switches, which sense physical tampering and opening of thehousing, are also located within partial enclosure 216. In theillustrated embodiment the case-open switches are each embodied in araised resilient dome 250 formed on key contact pad 230 and haveconductors 252 formed on an underside surface thereof. Domes 250preferably extend outwardly from the surface of key contact pad 230 to agreater extent than do domes 234. Alternatively, the case-open switchesmay be constructed and operative as described hereinabove with referenceto one of the embodiments shown FIGS. 1A, 1B, 13A-14B.

Disposed on electrical circuit board 240 underlying each of domes 250are a corresponding number of pairs of adjacent electrical contact pads254, each pair underlying a corresponding conductor 252. The arrangementof key contact pad 230 and of electrical circuit board 240 is such thatas long as the housing is closed, conductors 252 each are in electricalcontact with and between a corresponding pair of electrical contact pads254 lying thereunder and in registration therewith. This electricalcontact is ensured by the provision of pins 256 integrally formed onhousing element 202. When the housing is closed, pins 256 urgecorresponding protrusions 258 in key mat 212 towards partial enclosure216 and urge partial enclosure 216 and thus corresponding domes 250 andthe conductors 252, on the underside surfaces thereof, into electricalcontact with corresponding electrical contact pads 254.

When the housing is opened, no electrical contact exists betweenconductor 252 and corresponding pairs of electrical contact pads 254 orbetween the adjacent pads of the pair of electrical contact pads 254 anda suitable alarm or disablement occurs.

Disposed below electrical circuit board 240, there is provided aperipheral protective grid element 260 which includes an anti-tamperinggrid 262, preferably coupled to a flexible cable 264, which is in turnconnected to a connector 266 on electrical circuit board 240. Peripheralprotective grid element 260 preferably is located interiorly of the sidesurfaces 222 of enclosure 216. Fixedly attached to peripheral protectivegrid element 260, and preferably disposed therebelow, is a bottomprotective grid element 268 which includes an anti-tampering grid 270,which is coupled via contacts 272 and via a connector 274, which extendsthrough an aperture 276 formed in peripheral grid element 260, intoelectrical contact with contacts 278 on electrical circuit board 240.The anti-tampering grids 262 and 270 are coupled to anti-tamperingdetection circuitry 248.

In the illustrated embodiment of FIGS. 2A, 2B and 2C, there is alsoprovided a structural peripheral enclosure element 280 which is disposedinteriorly of the sides 222 of the flexible resilient protective partialenclosure 216 and which provides a peripheral seating surface 282 forelectrical circuit board 240.

Reference is now made to FIG. 3, which is a generalized illustration ofthe electrical connections described hereinabove and includes referencenumerals corresponding to both of the above-described embodiments shownrespectively in FIGS. 1A-1C and 2A-2C. It may be appreciated from FIG. 3that all of the anti-tampering grids are connected to the anti-tamperingcircuitry which is located within the protective enclosure.

Reference is now made to FIGS. 4A and 4B, which are simplified explodedview illustrations, taken in respective opposite directions, of a securekeypad device constructed and operative in accordance with a furtherpreferred embodiment of the present invention, to FIG. 4C, which is asimplified illustration the secure keypad device of FIGS. 4A and 4B atvarious stages of disassembly, and to FIG. 5, which is a simplifiedillustration of electrical connections between anti-tampering elementsin the embodiments of FIGS. 4A-4C. FIG. 4C is provided to betterillustrate the various elements of the keypad device of FIGS. 4A and 4B.

As seen in FIGS. 4A-5, there is provided a secure keypad device 400including a housing element 402 which, together with a back panel (notshown), defines a keypad device housing. Housing element 402 includes,on a top surface 404 thereof, a display aperture 406, through which adisplay (not shown) may be viewed, and an array 408 of key apertures410.

An anti-tamper board 412, which includes an anti-tampering grid 414formed of a multiplicity of interconnected anti-tampering, electricalconductors 416, underlies top surface 404 and is provided with keyapertures 420 in registration with key apertures 410. Fixedly andelectrically coupled to anti-tamper board 412 is a peripheralanti-tamper keypad enclosure 422, which preferably includes ananti-tampering grid 423 formed of a multiplicity of interconnectedanti-tampering electrical conductors.

A key mat 432, preferably formed of a resilient plastic or rubber,defines a plurality of depressible keys 434, preferably integrallyformed with mat 432, which partially extend through key apertures 410and 420 and have conductors 436 formed on corresponding bottom facingsurfaces 438 thereof.

An electrical circuit board 440, which functions, inter alia, as a keycontact board, is disposed in predetermined spaced relationship with keymat 432 and defines a plurality of pairs of adjacent electrical contactpads 442, each pair underlying a corresponding conductor 436. Thearrangement of key mat 432 and of electrical circuit board 440 is suchthat depression of a key 434 by the finger of a user causes conductor436 to establish electrical contact with and between a correspondingpair of electrical contact pads 442 lying thereunder and in registrationtherewith. When key 434 is not depressed, no electrical contact existsbetween conductor 436 and a pair of corresponding electrical contactpads 442 or between the adjacent pads of the pair.

Circuit board 440 preferably includes an anti-tampering grid 444thrilled of a multiplicity of interconnected anti-tampering electricalconductors. Fixedly coupled to circuit board 440 and an additionalelectrical circuit board 456 is a peripheral antis tamper enclosure 460which preferably includes an anti-tampering grid 461 formed of amultiplicity of interconnected anti-tampering electrical conductors.

Electrical connectors 446, which extend through apertures 443 formed inperipheral anti-tamper enclosure 460, are coupled via contacts 445 togrid 444 and arranged for mating connection through contacts 457 with ananti-tampering grid 454, formed of a multiplicity of interconnectedanti-tampering, electrical conductors, which is formed on additionalelectrical circuit board 456.

Electrical connectors 471 extend through apertures 473 formed inperipheral anti-tamper keypad enclosure 422 and through apertures 475formed in circuit board 440, each underlying corresponding aperture 473.Electrical connectors 471 are coupled via contacts 477 to anti-tamperinggrid 461 and arranged for mating connection through contacts 479 withanti-tampering grid 414.

Electrical connectors 481, which extend through apertures 483 formed inkeymat 432, are coupled via contacts 485 to anti-tampering grid 414 andarranged for mating connection through contacts 487 with anti-tamperinggrid 444.

Anti-tampering grid 423 is soldered via soldering points 489 on board422 and soldering points 491 on board 412 to anti-tampering grid 414.

It is thus appreciated that the anti tampering grids 444, 414, 454, 423and 461 on boards 440, 412 and 456 and enclosures 422 and 460,respectively, are interconnected so as to define an anti-tamperingenclosure, which is coupled to and physically encloses anti-tamperingdetection circuitry 493.

It is appreciated that the anti-tampering grids can be interconnected innumerous ways using various types of connectors.

In accordance with a preferred embodiment of the present invention,case-open switches, which sense physical tampering and opening of thehousing, are also located within the anti-tampering enclosure. In theillustrated embodiment, the case-open switches are each embodied inconductors 462 mounted on key mat 432 and corresponding pair ofelectrical contact pads 464 mounted on board 440. Alternatively, thecase-open switches may be constructed and operative as describedhereinabove with reference to one of the embodiments shown FIGS. 1A, 1B,13A-14B.

When the housing is closed, pins 465, which extend through apertures 466in board 412, force conductors 462 and corresponding pair of electricalcontact pads 464 into electrical contact or between the adjacent pads ofthe pair. When the housing is opened, pins 465 no longer forceconductors 462 and corresponding pair of electrical contact pads 464into electrical contact and as a result electrical contact no longerexists between conductors 462 and corresponding pair of electricalcontact pads 464 or between the adjacent pads of the pair and a suitablealarm or disablement occurs.

Reference is now made FIGS. 6A and 6B, which are simplified explodedview illustrations, taken in respective opposite directions, of a securekeypad device constructed and operative in accordance with an additionalpreferred embodiment of the present invention, and to FIG. 7, which is asimplified illustration of electrical connections between anti-tamperingelements in the embodiments of FIGS. 6A and 6B.

As seen in FIGS. 6A-7, there is provided a secure keypad device 600including a housing element 602 which, together with a back panel (notshown), defines a keypad device housing. Housing element 602 includes,on a top surface 604 thereof, a display aperture 606, through which adisplay (not shown) may be viewed, and an array 608 of key apertures610.

An anti-tamper board 612, which includes an anti-tampering grid 614formed of a multiplicity of interconnected anti-tampering electricalconductors 616, underlies top surface 604 and is provided with keyapertures 620 in registration with key apertures 610. Fixedly andelectrically coupled to anti-tamper board 612 is a peripheralanti-tamper keypad enclosure 622, which preferably includes ananti-tampering grid 624 formed of a multiplicity of interconnectedanti-tampering electrical conductors.

A key mat 632, preferably formed of a resilient plastic or rubber,defines a plurality of depressible keys 634 which partially extendthrough key apertures 610 and 620. A flexible resilient protectiveelement 636, preferably a resilient generally planar pad formed offlexible and resilient plastic or rubber which includes ananti-tampering grid 638 formed of a multiplicity of interconnectedanti-tampering electrical conductors, is provided. An electrical cable640 is coupled to grid 638.

Disposed below element 636 is a key contact pad 642, preferably aresilient generally planar pad formed of flexible and resilient plasticor rubber, having an array 644 of raised resilient domes 646 havingconductors 648 formed on corresponding bottom facing surfaces 650thereof.

An electrical circuit board 660 is disposed in predetermined spacedrelationship with key mat 632 and defines a plurality of pairs ofadjacent electrical contact pads 662, each pair underlying acorresponding conductor 648. The arrangement of key mat 632 and ofelectrical circuit board 660 is such that depression of a key 634 by thefinger of a user causes conductor 648 to establish electrical contactwith and between a corresponding pair of electrical contact pads 662lying thereunder and in registration therewith. When key 634 is notdepressed, no electrical contact exists between conductor 648 and a pairof corresponding pads 662 or between the adjacent pads of the pair.

Circuit board 660 preferably includes an anti-tampering grid 664, formedof a multiplicity of interconnected anti-tampering electricalconductors. Fixedly and electrically coupled to board 660 and to anadditional electrical circuit board 670 is a peripheral anti-tamperenclosure 672, which preferably includes an anti-tampering grid 676formed of a multiplicity of interconnected anti-tampering electricalconductors.

Electrical connectors 666, which extend through apertures 667 inperipheral anti-tamper enclosure 672, are coupled via contacts 665 togrid 664 and arranged thr mating connection through contacts 669 with ananti-tampering grid 668 formed of a multiplicity of interconnectedanti-tampering electrical conductors on additional electrical circuitboard 670.

Electrical connectors 677 extend through apertures 679 formed inperipheral anti-tamper keypad enclosure 622 and through apertures 681formed in board 660, each underlying corresponding aperture 679.Electrical connectors 677 are coupled via contacts 673 to anti-tamperinggrid 676 and arranged for mating connection through contacts 675 withanti-tampering grid 614.

Flexible electrical cable 640 is connected to a connector 683 onelectrical circuit board 660.

Electrical connectors 691 extend through apertures 693 formed inflexible element 636 and through apertures 695 formed in key contact pad642 and corresponding apertures 696 formed in key mat 632. Electricalconnectors 691 are coupled via contacts 697 to anti-tampering grid 664and arranged for mating connection through contacts 699 with ananti-tampering grid 614.

Anti-tampering grid 624 is soldered to anti-tampering grid 614.

It is thus appreciated that the anti tampering grids 614, 664, 668, 638,624 and 676, on boards 612, 660 and 670, element 636 and enclosures 622and 672, respectively, are interconnected so as to define ananti-tampering enclosure, which is coupled to and physically enclosesanti-tampering detection circuitry 674.

In accordance with a preferred embodiment of the present invention,case-open switches, which sense physical tampering and opening of thehousing, are also located within the anti-tampering enclosure. In theillustrated embodiment the case-open switches are each embodied inconductors 680 mounted on the bottom facing of domes 641 of key contactpad 642 and corresponding pairs of electrical contact pads 682 mountedon board 660. Alternatively, the case-open switches may be constructedand operative as described hereinabove with reference to one of theembodiments shown FIGS. 1A, 1B, 13A-14B.

When the housing is closed, pins 684, which extend through apertures 686in board 612, urge corresponding protrusions 631 on key mat 632 towardselement 636 and key contact pad 642 and urge domes 641 on key contactpad 642 towards board 660 and thus force conductors 680 and pair ofelectrical contact pads 682 into electrical contact. When the housing isopened, pins 684 no longer force conductors 680 and pair of electricalcontact pads 682 into electrical contact and as a result electricalcontact no longer exists between conductors 680 and pair of electricalcontact pads 682 and a suitable alarm or disablement occurs.

Reference is now made to FIG. 8, which is a simplified exploded viewillustration of a secure keypad device constructed and operative inaccordance with a still further preferred embodiment of the presentinvention, and to FIGS. 9A & 9B, which are simplified sectionalillustrations of part of the device of FIG. 8, taken along lines IX-IXin FIG. 8, in respective key non-depressed and key depressed operativeorientations.

As seen in FIGS. 8-9B, there is provided a secure keypad device 800including a housing element 802 which, together with a back panel (notshown), defines a keypad device housing. Housing element 802 includes,on a top surface 804 thereof, a display aperture 806, through which adisplay (not shown) may be viewed, and an array 808 of key apertures810.

An anti-tamper board 812, which includes an anti-tampering grid 814formed of a multiplicity of interconnected anti-tampering electricalconductors, underlies top surface 804 and is provided with key apertures820 in registration with key apertures 810. Fixedly and electricallycoupled to anti-tamper hoard 812 is a peripheral anti-tamper keypadenclosure 822, which preferably includes an anti-tampering grid 824formed of a multiplicity of interconnected anti-tampering electricalconductors.

A key mat 832, preferably formed of a resilient plastic or rubber,defines a plurality of depressible keys 834 which partially extendthrough key apertures 810 and 820. Conductors 836 are formed on key mat832.

Pairs of adjacent electrical contact pads 838 are located on board 812in registration with conductors 836 and are arranged such that when keys834 are in a non-depressed operative orientation, such as that shown inFIG. 9A, electrical contact exists between conductors 836 and pairs ofadjacent electrical contact pads 838 lying thereover and in registrationtherewith and between those pairs of adjacent electrical contact pads838. When keys 834 are in a depressed operative orientation, such asthat shown in FIG. 9B, no electrical contact exists between conductors836 and pairs of adjacent electrical contact pads 838 lying thereoverand in registration therewith and between those pairs of adjacentelectrical contact pads 838.

An electrical circuit board 840 is disposed in predetermined spacedrelationship with key mat 832. Board 840 preferably includes ananti-tampering grid 844 formed of a multiplicity of interconnectedanti-tampering electrical conductors. Electrical connectors 846 arecoupled to grid 844 and arranged for mating connection with ananti-tampering grid 854, formed of a multiplicity of interconnectedanti-tampering electrical conductors, which is formed on an additionalelectrical circuit board 856. Fixedly and electrically coupled to boards840 and 856 is a peripheral anti-tamper enclosure 858 which preferablyincludes an anti-tampering grid 859, formed of a multiplicity ofinterconnected anti-tampering electrical conductors. It is thusappreciated that the anti tampering grids 844, 854 and 859, on boards840 and 856 and peripheral anti-tamper enclosure 858, respectively, areinterconnected so as to define an anti-tampering enclosure, which iscoupled to and physically encloses anti-tampering detection circuitry(not shown). It is also appreciated that anti tampering grids 814 and824 on board 812 and enclosure 822 are coupled to anti-tamperingcircuitry (not shown) and preferably interconnected to anti tamperinggrids 844, 854 and 859 on boards 840 and 856 and enclosure 858.

In accordance with a preferred embodiment of the present invention,case-open switches, which sense physical tampering and opening of thehousing, are also located within the anti-tampering enclosure. In theillustrated embodiment, the case-open switches are each embodied inconductors (not shown) mounted on key mat 832 and formed on undersidesurface thereof, and corresponding pair of electrical pads 864 mountedon board 840. Alternatively, the case-open switches may be constructedand operative as described hereinabove with reference to one of theembodiments shown FIGS. 1A, 1B, 13A-14B.

When the housing is closed, pins (not shown) extend through apertures(not shown) in board 812 and force pair of electrical contacts 864 andcorresponding conductors (not shown) on key mat 832 into electricalcontact. When the housing is opened, pins 864 no longer force conductorson key mat 832 and pair of electrical pads 864 into electrical contactand as a result electrical contact no longer exists between conductorson key mat 832 and pair of electrical contacts 864 and a suitable alarmor disablement occurs.

Reference is now made to FIG. 10, which is a simplified exploded viewillustration of a secure keypad device constructed and operative inaccordance with a yet further preferred embodiment of the presentinvention, and to FIGS. 11A & 11B, which are simplified sectionalillustrations of part of the device of FIG. 10, taken along lines XI-XIin FIG. 10, in respective key non-depressed and key depressed operativeorientations.

As seen in FIGS. 10-11B, there is provided a secure keypad device 900including a housing element 902 which, together with a back panel (notshown), defines a keypad device housing. Housing element 902 includes adisplay aperture 906, through which a display (not shown) may be viewed,and an array 908 of key apertures 910.

An anti-tamper board 912, which includes an anti-tampering grid 914formed of a multiplicity of interconnected anti-tampering electricalconductors, underlies top surface of housing element 902 and is providedwith key apertures 920 in registration with key apertures 910. Fixedlyand electrically coupled to anti-tamper board 912 is a peripheralanti-tamper keypad enclosure 922, which preferably includes ananti-tampering grid 923, formed of a multiplicity of interconnectedanti-tampering electrical conductors.

A key mat 932, preferably formed of a resilient plastic or rubber,defines a plurality of depressible keys 934 which partially extendthrough key apertures 910 and 920. Conductors 936 are formed on anunderside surface 938 of key mat 932, preferably on opposite sides ofeach of keys 934.

An electrical circuit board 940, which functions, inter alia, as a keycontact board, is disposed in predetermined spaced relationship with keymat 932 and defines a plurality of pairs of adjacent electrical contactpads 942, each pair underlying a corresponding conductor 936.

When keys 934 are in a non-depressed operative orientation, such as thatshown in FIG. 11A, electrical contact does not exist between conductors936 and pairs of adjacent electrical contact pads 942 lying thereunderand in registration therewith and between those pairs of adjacentelectrical contact pads 942. When keys 934 are in a depressed operativeorientation, such as that shown in FIG. 11B, electrical contact existsbetween conductors 936 and pairs of adjacent electrical contact pads 942lying thereunder in registration therewith and between those pairs ofadjacent electrical contact pads 942.

Board 940 preferably includes an anti-tampering grid 944, formed of amultiplicity of interconnected anti-tampering electrical conductors.Electrical connectors 946 are coupled to grid 944 and arranged formating connection with an anti-tampering grid 954, formed of amultiplicity of interconnected anti-tampering electrical conductors,which is formed on an additional electrical circuit board 956. Fixedlyand electrically coupled to boards 940 and 956 is a peripheralanti-tamper enclosure 958 which preferably includes an anti-tamperinggrid 957 formed of a multiplicity of interconnected anti-tamperingelectrical conductors. It is appreciated that the anti tampering grids944, 954 and 957 on boards 940 and 956 and peripheral anti-tamperenclosure 958, respectively, are interconnected so as to define ananti-tampering enclosure, which is coupled to and physically enclosesanti-tampering detection circuitry 959. Electrical connectors 980 and982 preferably couple grids 914 and 923 on board 912 and enclosure 922,respectively, to anti-tampering detection circuitry 959.

In accordance with a preferred embodiment of the present invention,case-open switches, which sense physical tampering and opening of thehousing are also located within the anti-tampering enclosure. In theillustrated embodiment the case-open switches are each embodied inconductors 962 mounted on key mat 932 and corresponding conductors (notshown) mounted on board 940. Alternatively, the case-open switches maybe constructed and operative as described hereinabove with reference toone of the embodiments shown FIGS. 1A, 1B, 13A-14B.

When the housing is closed, pins 966 extend through apertures 968 inboard 912 and force conductors 962 into electrical contact with thecorresponding conductors on board 940. When the housing is opened, pins966 no longer force conductors 962 into electrical contact with thecorresponding conductors on board 940 and as a result electrical contactno longer exists between conductors 962 and the corresponding conductorson board 940 and a suitable alarm or disablement occurs.

Reference is now made to FIGS. 12A and 12B, which are simplifiedexploded view illustrations, taken in respective opposite directions, ofa secure keypad device constructed and operative in accordance withstill another preferred embodiment of the present invention.

As seen in FIGS. 12A and 12B, there is provided a secure keypad device1100 including a housing element 1102 which, together with a hack panel(not shown), defines a keypad device housing. Housing element 1102includes, on a top surface 1104 thereof; a display aperture 1106,through which a display (not shown) may be viewed, and an array 1108 ofdepressible keys 1110, preferably integrally formed with housing element1102.

Keys 1110 are preferably formed of a resilient plastic or rubber andpartially extend above top surface 1104 of housing element 1102. As seenparticularly in section A-A enlargement in FIG. 12A, a contact surface1112 of each of keys 1110 extends below top surface 1104 of housingelement 1102. Keys 1110 preferably include an attachment portion 1113and a connection portion 1114.

A flexible resilient protective partial enclosure 1116, which includesan anti-tampering grid 1118, formed of a multiplicity of interconnectedanti-tampering electrical conductors, on a top surface 1120 thereof andon side surfaces 1122 thereof, is provided. A flexible cable 1124 iscoupled to grid 1118.

Disposed within protective partial enclosure 1116, underlying topsurface 1120, is a key contact pad 1130. Key contact pad 1130 ispreferably a resilient, generally planar, pad thrilled of flexible andresilient plastic or rubber, having an array 1132 of raised resilientdomes 1134 with conductors 1136 being formed on corresponding bottomfacing surfaces 1138 thereof.

Disposed in predetermined spaced relationship with key contact pad 1130is an electrical circuit board 1140, which functions, inter alia, as akey contact board, defining a plurality of pairs of adjacent electricalcontact pads 1142, each pair underlying a corresponding conductor 1136,preferably made of carbon, metal or combination of carbon/metal. Thearrangement of key contact pad 1130 and of electrical circuit board 1140is such that depression of a key 1110 by the finger of a user causesconductor 1136 to establish electrical contact with and between acorresponding pair of electrical contact pads 1142 lying thereunder andin registration therewith. When key 1110 is not depressed, no electricalcontact exists between conductor 1136 and a pair of correspondingelectrical contact pads 1142 or between the adjacent pads of the pair.

Electrical circuit hoard 1140 preferably includes an anti-tampering grid1144 formed of a multiplicity of interconnected anti-tamperingelectrical conductors. An electrical connector 1146 is arranged formating connection with flexible cable 1124. The anti-tampering grids1118 and 1144 are coupled to anti-tampering detection circuitry 1148.

In accordance with a preferred embodiment of the present invention,case-open switches, which sense physical tampering and opening of thehousing, are also located within partial enclosure 1116. In theillustrated embodiment, the case-open switches are each embodied in araised resilient dome 1150 formed on key contact pad 1130 and haveconductors 1152 formed on an underside surface thereof. Domes 1150preferably extend outwardly from the surface of key contact pad 1130 toa greater extent than do domes 1134. Alternatively, the case-openswitches may be constructed and operative as described hereinabove withreference to one of the embodiments shown FIGS. 1A, 1B, 13A-14B.

Disposed on electrical circuit board 1140 underlying each of domes 1150are a corresponding number of pairs of adjacent electrical contact pads1154, each pair underlying a corresponding conductor 1152. Thearrangement of key contact pad 1130 and of electrical circuit board 1140is such that as long as the housing is closed, conductors 1152 each arein electrical contact with and between a corresponding pair ofelectrical contact pads 1154 lying thereunder and in registrationtherewith. This electrical contact is ensured by the provision of pins1156 integrally formed on housing element 1102. When the housing isclosed, pins 1156 urge element 1116 and thus corresponding domes 1150 oncontact pad 1130, and thus corresponding conductors 1152, on theunderside surfaces thereof, into electrical contact with correspondingelectrical contact pads 1154.

When the housing is opened, no electrical contact exists betweenconductor 1152 and corresponding pairs of electrical contact pads 1154or between the adjacent pads of the pair of electrical contact pads 1154and a suitable alarm or disablement occurs.

Disposed below electrical circuit board 1140, there is provided aperipheral protective grid element 1160 which includes an anti-tamperinggrid 1162, preferably coupled to a flexible cable 1164, which is in turnconnected to a connector 1166 on electrical circuit board 1140.Peripheral protective grid element 1160 preferably is located interiorlyof the side surfaces 1122 of enclosure 1116. Fixedly attached toperipheral protective grid element 1160 and preferably disposedtherebelow is a bottom protective grid element 1168 which includes ananti-tampering grid 1170, which is coupled via contacts 1172 and via aconnector 1174 which extends through an aperture 1176 formed inperipheral grid element 1160 into electrical contact with contacts 1178on electrical circuit board 1140. The anti-tampering grids 1162 and 1170are coupled to anti-tampering detection circuitry 1148.

It is appreciated by persons skilled in the art that the presentinvention is not limited by what has been particularly shown anddescribed hereinabove. Rather the scope of the present inventionincludes both combinations and subcombinations of various featuresdescribed hereinabove as well as variations and modifications theretowhich would occur to a person of skill in the art upon reading the abovedescription and which are not in the prior art.

1. A device comprising: an enclosure; circuitry located on an electricalcircuit board within said enclosure; at least one switch assemblyoperative to sense when said enclosure is opened; and tamper indicationcircuitry operative to receive an input from said at least one switchassembly and to provide an output indication of possible tampering withsaid circuitry located on said electrical circuit board within saidenclosure, said at least one switch assembly including a raisedresilient dome and an arrangement of electrical contacts located on saidelectrical circuit board, said electrical contacts including at leastfirst, second and third mutually concentric conductive pads allunderlying said dome, said at least first, second and third mutuallyconcentric conductive pads and said raised resilient dome beingconfigured and arranged such that as long as said enclosure is closed ina non-tampered state, said raised resilient dome is in electricalcontact with some but not all of said at least first, second and thirdmutually concentric pads, said tamper indication circuitry beingoperative such that when electrical connections between said at leastfirst, second and third mutually concentric conductive pads change fromthose in said non-tampered state, an output indication of possibletampering is provided.
 2. A device according to claim 1 and wherein saidat least first, second and third mutually concentric conductive pads areconnected to said tamper indication circuitry. 3-4. (canceled)
 5. Adevice according to claim 1 and wherein: said enclosure includes a topportion including key apertures; a plurality of keys are mounted in saidenclosure to have key depression travel paths in said enclosure, saidplurality of keys being associated with a substrate, which is disposedbelow said top portion; and anti-tampering electrical conductors arearranged between said top portion and said substrate thereby to preventunauthorized access to said substrate.
 6. A device according to claim 5and wherein said substrate is a flexible substrate.
 7. A deviceaccording to claim 5 and wherein said anti-tampering electricalconductors are disposed peripherally of said substrate.
 8. A deviceaccording to claim 5 and also comprising a plurality of key switchcontacts mounted on said substrate and arranged to be displaced into orout of electrical contact with a corresponding plurality of electricalswitches by depression of corresponding ones of said plurality of keysto at least a predetermined extent along corresponding ones of said keydepression travel paths.
 9. A device according to claim 5 and alsocomprising a plurality of key switch contacts mounted on said pluralityof keys and arranged to be displaced into or out of electrical contactwith a corresponding plurality of electrical switches by depression ofcorresponding ones of said plurality of keys to at least a predeterminedextent along corresponding ones of said key depression travel paths. 10.A device according to claim 5 and wherein said plurality of keys areintegrally formed with said substrate.
 11. A device according to claim 5and wherein said anti-tampering electrical conductors are electricallyconnected to anti-tampering detection circuitry.
 12. A device accordingto claim 5 and wherein said anti-tampering electrical conductors aredisposed above and below said substrate.
 13. A device according to claim12 and wherein said anti-tampering electrical conductors above saidsubstrate and said anti-tampering electrical conductors below saidsubstrate are electrically connected to anti-tampering detectioncircuitry.
 14. A device according to claim 12 and wherein saidanti-tampering electrical conductors above said substrate areelectrically connected to said anti-tampering electrical conductorsbelow said substrate. 15-19. (canceled)
 20. A device according to claim1 and wherein said raised resilient dome is in a first operativeorientation vis-à-vis said at least first, second and third mutuallyconcentric conductive pads when said enclosure is closed and is in asecond operative orientation vis-à-vis said at least first, second andthird mutually concentric conductive pads when said enclosure is open.21. A device according to claim 20 and also comprising at least oneurging element which normally urges said raised resilient dome into saidfirst operative orientation vis-à-vis said at least first, second andthird mutually concentric conductive pads when said enclosure is closed.22. A device according to claim 21 and also wherein said at least oneurging element is mounted on said enclosure.